The present invention relates to a document buffer and more particularly to an apparatus for buffering transport of document coated with liquid ink using conical screw conveyers.
For increasing the throughput of mailing machines, it is important to provide means for buffering transport of inked document exiting a liquid ink printer, such as an ink jet printer, so that the ink is relatively dry upon the document and will not smear. This presents a problem of storing the document during the drying period without leading to stoppages in the operation of the transport and in turn halting operation of the entire mailing system. Heretofore, it has been the practice to extend the path of travel for document to enable sufficient drying time prior to further manipulation of the document. Machines for drying articles, such as printed material, have often consisted of a long, substantially horizontal, conveyor belt on which articles to be dried are placed. A disadvantage of this type of machine is that, since they are longitudinally oriented, extending the path utilizes valuable space and consumes much time.
Recently, the present inventors conceived and developed a buffer apparatus to handle a continuous flow of freshly inked sheets at a high rate. A pending patent application, Ser. No. 08/174,870, filed Dec. 29, 1993, entitled APPARATUS FOR BUFFERING TRANSPORT OF DOCUMENT, assigned to the assignee of the instant patent application, describes the buffer apparatus. Although this arrangement worked satisfactorily, the present inventors found that the belt imparting motion to the screw conveyers caused unwanted movement away from the home position while adjusting the belt tension. In addition, the buffer apparatus required a more robust eject mechanism to control document movement from the buffer station to a document handler, such as an envelope flapper.